I don't really think a slipping clutch would even be a good start to a dyno test and surprised the guy even proceeded with a test,sorry but prefer to be honest,your cam as stated as mild,with stock valves that most likely isn't a bad thing,still really lost to why you are running 45's but I don't know your vent size,its important to remember you aren't after max HP @ the higher RPM range because you rarely drive there except the freeway,you really need a good power curve from 2500 to 5000.
Considering a good 2.0L stock motor can make 95bhp something is not right with your motor for that displacement.....should be lots more as suggested.
Tuning any aircooled engine to max power on a dyno is a recipe for destruction if timing isn't keep sensible many tuners don't know that.
Good luck.

The valve size and header size isn't a huge issue we're only talking .078" (2mm) smaller (your 42X36mm vs my 44x38mm) than what's in my 180hp 2600cc (78x102 w/9.5:1CR) and I also run a 1-5/8" header.

The main two things will be the cam and CR. My guess is the CR is also set way low.

I run a WEB cam 163/86b, .507/.497 lift 288*/298* duration.
With this cam you have to run between 9.0 and 9.5 CR, plus dual springs, CrMo retainers, keepers, pushrods and all the other valve train goodies. WEB says this is a race cam but to me it's a well rounded hot street cam for large displacement engines. Good, slight lumpy idle, gobbs of torque, for your engine spec it would be the one I recommend.

Timing I run 28* total, anything over 30* is too much, I bet you're pinging even if you can't hear it. At 36* your engine will have a short life.

On the clutch you definetly have a oil contamination issue, the stock clutch can handle 180 bhp, I cut my flywheel 2nd step an extra .010 for slightly more holding power.
I'm right on the clutch limit with my engine Hp and once last fall was the first time I felt any slip, after 5 years of hard launches.




BTW For some reason I thought you said a 80 stroke, but looking back I see it's 71X103mm so the standard base circle on the cam is fine.